Okay, I just posted this to the Midwest forum as well so apologies in advance - but I need a little help. I brewed a hefe last night and 24 hours later no airlock movement. I know the temp was well below 80* when I pitched. Can it be too low? Temp in the room where it is sitting is 63-64 degrees. Pretty sure sanitation is not an issue. What to do? Warm bath? Move to warmer room? Hope I can save this sucker . . . thanks all! Oh - and yes I aerated well.

Okay - sorry dudes. Guess I jumped the gun. Two hours ago I sat and watched that airlock for a good minute without even the slightest movement. Now it's bubbling its little heart out. I didn't touch anything. Just looked at it. Now it's fermenting. Maybe I willed it happen . . .

72 hours is a good rule at 65F. I like to keep my ales around 75F until the yeast are done growing and the bubbling starts.

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Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"

I guess this poses a good question though. How long should one wait without airlock movement before he really should freak out?

AHU

Bubbling of an airlock is dependant on having a perfect seal on the fermenter, something that doesn't always happen. I use other clues such as the formation of a krausen, decrease in SG, temperature rise, etc.
To answer your question, I don't even think twice about a 72 hour lagtime- if I'm using a dry yeast that has not been proofed.